Cottonwood Dam (park)
Cottonwood Dam (park) is an earth dam located in Park County, Montana, built in 1953. It carries a High hazard potential classification and has a poor condition assessment.
About Cottonwood Dam (park)
The primary purpose of Cottonwood Dam (park) is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by State Water Projects (state). It impounds the Cottonwood Creek near Wilsall.
The dam stands 39 feet tall and stretches 610 feet across, creates a reservoir covering 235 acres, has a maximum storage capacity of 3,670 acre-feet, and collects water from a drainage area of 34 square miles. Completed in 1953, the structure is well into its service life at over 50 years old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 05/01/2024.
At 39 feet, this dam is taller than 86% of dams nationwide.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Montana dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Montana |
| County | Park |
| Nearest City | Wilsall |
| River/Stream | Cottonwood Creek |
| Coordinates | 46.03425, -110.68223 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 39 ft |
| Dam Height | 39 ft |
| Dam Length | 610 ft |
| Year Completed | 1953 (73 years old) |
Storage & Hydraulics
| NID Storage | 3,670 acre-ft |
| Max Storage | 3,670 acre-ft |
| Normal Storage | 1,905 acre-ft |
| Surface Area | 235 acres |
| Drainage Area | 34 sq mi |
| Max Discharge | 217 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | STATE WATER PROJECTS |
| Owner Type | State |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 05/01/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MT00021 |
| Federal ID | MT00021 |
| More Info | State Dam Safety Program |